Polyisocyanurate coverboards with improved fire resistance

ABSTRACT

A construction board comprising a foam body having first and second planar surfaces, said foam body including a polyisocyanurate foam matrix defining a plurality of closed cells, said closed cells being at least substantially devoid of hydrocarbon blowing agents, and said foam body being characterized by a density, pursuant to ASTM C303, of at least 2.5 lbs/ft 3 ; and a facer disposed on a planar surface of said foam body, said facer including a glass substrate having an internal planar surface proximate to said foam body and an external planar surface opposite said foam body, a first coating disposed on said external surface, and a second coating disposed on or proximate to said internal surface, where said first coating disposed on said external surface includes an inert filler, and where said second coating disposed on or proximate to said internal surface includes intumescent material.

This application claims the benefit of U.S. Provisional Application Ser.No. 62/501,802 filed on May 5, 2017, which is incorporated herein byreference.

FIELD OF THE INVENTION

Embodiments of the present invention are directed toward composite highdensity polyisocyanurate cover boards that have improved fire propertiesdue, at least in part, to the absence of a hydrocarbon blowing agent andthe presence of a glass facer that includes an external coatingincluding inert filler and an interfacial coating including intumescentmaterial.

BACKGROUND OF THE INVENTION

Coverboards and recovery boards are often used in commercial roofingsystems to provide roofs with fire barrier properties, protection fromfoot traffic, and protection from environmental forces such as hail. Acommonly used coverboard is a fiberglass faced gypsum board, which issold under the tradename DENSDECK. Notably, these boards have found wideacceptance because they are noncombustible, per ASTM E136, have beencertified by UL for fire resistance under the 790 and 1256classifications, meet FM class 1 approvals for metal decks, and meetASTM E84 standards for flame and smoke. While fire resistant anddimensionally stable, these construction boards have appreciable weightand structure, which impacts transportation, movement on a job site, andoverall ease of installation. There is a desire, therefore, forconstruction boards with similar fire resistance and dimensionalstability that are lighter and more manageable (e.g., easier to cut).

Polyisocyanurate coverboards are known. For example, U.S. PublicationNo. 2006/0179749 teaches high density polyisocyanurate constructionboards for use as a coverboard or recover board. These boards may becharacterized by having a density above 2.5 lbs/ft³ and an index of atleast 175. These boards can include a hydrocarbon, such as a pentaneisomer, as an insulating agent, which compounds also serve as blowingagents during the manufacture of the foam. These construction boardsalso carry facer materials such as cellulosic, glass, or foil facers. Inorder to provide these boards with fire resistance, a fire retardant,such as tri(monochloropropyl) phosphate is included within the foamforming materials, especially in the presence of flammable blowingagents such as pentane isomers.

U.S. Publication No. 2010/0031603 is likewise directed toward highdensity polyisocyanurate construction boards that meet the requirementsimposed by UL 790 for flame spread. These boards have a density ofgreater than 2.5 lbs/ft³, an iso index of at least 270, and a cellularbody that includes at least 5.0 wt. % flame retardant.

While polyisocyanurate coverboards and recover boards are widely used inthe industry, they do not meet all of the standards, especially thoserelated to flame resistance, that have been achieved by fiberglass facedgypsum board.

SUMMARY OF THE INVENTION

One or more embodiments of the present invention provide a constructionboard comprising a foam body having first and second planar surfaces,said foam body including a polyisocyanurate foam matrix defining aplurality of closed cells, said closed cells being at leastsubstantially devoid of hydrocarbon blowing agents, and said foam bodybeing characterized by a density, pursuant to ASTM C303, of at least 2.5lbs/ft³; and a facer disposed on a planar surface of said foam body,said facer including a glass substrate having an internal planar surfaceproximate to said foam body and an external planar surface opposite saidfoam body, a first coating disposed on said external surface, and asecond coating disposed on or proximate to said internal surface, wheresaid first coating disposed on said external surface includes an inertfiller, and where said second coating disposed on or proximate to saidinternal surface includes intumescent material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a coverboard according to aspects ofthe present invention.

FIG. 2 is a cross-sectional view of a coverboard according to aspects ofthe present invention.

FIG. 3 is a perspective view of a roofing system according to aspects ofthe present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the invention are based, at least in part, on thediscovery of high density polyisocyanurate coverboards that demonstrateimproved flame resistance. In one or more embodiments, thepolyisocyanurate boards are substantially devoid of hydrocarbon blowingagents and carry a glass facer that includes an external coatingincluding inert filler and an interfacial coating that includesintumescent filler. In particular embodiments, the facer also includesan intermediary layer including inert filler. Advantageously, thecoverboards of the present invention have zero flame spread and zerosmoke development when tested in accordance with ASTM E84. While thehigh density polyisocyanurate boards contemplated in the prior art haveincreased flame resistance, owing in part to the high levels of flameretardant used within the boards, the prior art high density boards donot meet the requirements of a class 1 roof according to ASTM E84.Additionally, it is contemplated that the coverboards of the presentinvention can be used to prepare roof systems over both combustible andnon-combustible decks that meet the requirements of UL 790 without theuse of gypsum-based construction boards. It is also contemplated thatthe coverboards of the present invention can achieve FM class 1approvals for steel deck insulated roofs without the use of gypsum-basedcoverboards.

Coverboard Construction

Construction boards according to embodiments of the present inventioncan be described with reference to FIG. 1, which shows constructionboard 10, which may also be referred to as coverboard 10, recoverboard10, roof board 10, fire-barrier board 10, or simply board 10. As shown,board 10, which is generally planar in configuration, includes foam body12, which may also be referred to as foam core 12, and at least onefacer 14. In one or more embodiments, board 10 also includes an opposedfacer 14′.

Facer 14, as well as optional facer 14′, includes glass substrate 18,18′, external coating 16, 16′, and interfacial coating 20, 20′. Externalcoating 16, 16′ includes inert filler. Interfacial coating 20, 20′includes intumescent material 22, 22′.

It should be appreciated that interfacial coating 20, 20′ is disposedbetween foam body 12 and glass substrate 18. External coating layers 16,16′, on the other hand, are disposed on the external surface 17, 17′ ofglass substrate 18, which is opposite foam core 12 and internal surface19 of glass substrate 18 onto which intermediary coating 20 is disposed.

An alternate embodiment is shown in FIG. 2, where coverboard 10′likewise includes foam body 12, facer 14, and optional facer 14′. Facer14, 14′ include external coating 16, 16′, and interfacial coating 20,20′. Additionally, facer 14, 14′ includes an additional coating layer30, 30′ disposed between glass substrate 18, 18′ and interfacial coating20, 20′. In one or more embodiments, additional coating layer 30, 30′,which may be referred to as internal coating layer 30, 30′, iscompositionally the same or similar to external coating 16, 16′. Asshould be evident from FIG. 2, interfacial coating layer 30, 30′ is notdisposed on internal surface 19 of substrate 18 but is instead proximatethereto since it is disposed on coating 30.

Foam Core

In one or more embodiments, foam layer 12 includes a rigid closed-cellfoam structure. In one or more embodiments, foam layer 12 may include apolyurethane or polyisocyanurate foam. As the skilled personappreciates, the closed-cell foam includes a plurality of cells and aninterconnected network of solid struts or plates that form the edges andfaces of the cells. The solid portion (i.e., the interconnected network)is formed from the foam-forming material (e.g., the polyurethane orpolyisocyanurate). The solid portion of foam layer 12 (i.e., the matrix)may include other constituents as is generally known in the art. As willbe discussed in greater detail below, additional frame or fire-resistantmaterials can be dispersed within the solid portion of foam layer 12.Additionally, in one or more embodiments, the expandable graphite can bedispersed within the solid portion of foam layer 12 in combination witha non-halogenated flame retardant.

In one or more embodiments, foam layer 12 may be characterized bydensity that is greater than 2.5 pounds per cubic foot (12.2 kg/m²), asdetermined according to ASTM C303, in other embodiments the density isgreater than 2.8 pounds per cubic foot (13.7 kg/m²), in otherembodiments greater than 3.0 pounds per cubic foot (14.6 kg/m²), andstill in other embodiments greater than 3.5 pounds per cubic foot (17.1kg/m²). In one or more embodiments, the density of foam layer 12 of therecovery boards may be less than 20 pounds per cubic foot (97.6 kg/m²),in other embodiments less than 10 pounds per cubic foot (48.8 kg/m²), inother embodiments less than 6 pounds per cubic foot (29.3 kg/m²), inother embodiments less than 5.9 pounds per cubic foot (28.8 kg/m²), inother embodiments less than 5.8 pounds per cubic foot (28.3 kg/m²), inother embodiments less than 5.7 pounds per cubic foot (27.8 kg/m²), inother embodiments less than 5.6 pounds per cubic foot (27.3 kg/m²), andstill in other embodiments less than 5.5 pounds per cubic foot (26.9kg/m²). Foam construction boards having a foam layer of similar natureare described in U.S. Publ. Nos. 2006/0179749 and 2010/0031603, whichare incorporated herein by reference.

Where the density of foam layer 12 is greater than 2.5 pounds per cubicfoot, it may be advantageous for foam layer 12 to be characterized by anISO Index, as determined by PIR/PUR ratio as determined by IRspectroscopy using standard foams of known index (note that ratio of 3PIR/PUR provides an ISO Index of 300) of at least 180, in otherembodiments at least 200, in other embodiments at least 220, in otherembodiments at least 270, in other embodiments at least 285, in otherembodiments at least 300, in other embodiments at least 315, and inother embodiments at least 325. In these or other embodiments, the ISOIndex may be less than 360, in other embodiments less than 350, in otherembodiments less than 340, and in other embodiments less than 335.

In one or more embodiments, the thickness of foam layer 12 may begreater than 0.5 cm, in other embodiments greater than 1, and in otherembodiments greater than 2 cms. In these or more embodiments, thethickness of foam layer 12 may be less than 15 cm, in other embodimentsless than 12, and in other embodiments less than 8 cms. In one or moreembodiments, the thickness of foam layer 12 may be from about 0.5 toabout 15 cms, in other embodiments from about 1 to about 12 cms, and inother embodiments from about 2 to about 8 cms.

According to aspects of the present invention, foam body 12, whichincludes cellular matrix 24 that forms closed cells 26 is substantiallydevoid of hydrocarbon blowing agents. Substantially devoid refers tothat amount or less that does not have an appreciable impact on theconstruction boards of the present invention, particularly as the impactrelates to the flammability of the construction boards. In one or moreembodiments, closed cells 26 include carbon dioxide, air, or a vacuum orpartial vacuum. As those skilled in the art appreciate, the presence ofcarbon dioxide can result from the use of water as a blowing agentduring the manufacture of the foam. These techniques will be describedin greater detail below. In one or more embodiments, foam body 12, andmore particularly closed cells 26, include less than 2, in otherembodiments less than 0.5, and in other embodiments less than 0.1percent by volume hydrocarbon blowing agents. In particular embodiments,closed cells 26 are devoid of halogenated organic compounds.

Glass Substrate

In one or more embodiments, substrate 18, 18′ is an inorganic substrate.In particular embodiments, the substrate is a non-woven glass mat, andtherefore reference may be made to glass mat 18, 18′. In one or moreembodiments, the non-woven fiberglass mats include glass fibers and abinder that binds the glass fibers together and maintains the fibers ina mat form. Any type of glass fiber mat can be used in the compositeboard. For example, a non-woven glass fiber mat can be made with glassfibers, the fibers can be bonded with an aqueous thermosetting resinsuch as, for example, urea formaldehyde or phenolic resole resins. Asthe skilled person will appreciate, these binder resins are conventionalin the art of non-woven glass mats, and the skilled person willunderstand that the coating (e.g., coating 16, 16′), as taught herein,is distinct, in both composition and structure, from this binder.

In one or more embodiments, the dimensional and weight characteristicsof glass substrate 18, 18′ are not particularly limited, and can dependon the specific application and desired properties of the coverboard.For example, the basis weight of glass substrate 22 (or 32) can be fromabout 50 grams per square meter to about 150 grams per square meter. Thethickness of glass substrate 22 (or 32) can be, for example, from about0.015 inch to about 0.05 inch (about 0.038 to about 0.13 cm). The basisweight and thickness characteristics can be adjusted depending upon thedesired rigidity, strength and weight of the composite board.

In one or more embodiments, the thickness of glass substrate 22 (or 32)(absent the coating layer described herein) may be from about 0.01 toabout 1.00 inch (about 0.03 to about 2.54 cm) or in other embodimentsfrom about 0.015 to about 0.05 inches thick (about 0.038 to about 0.13cm).

The dimensional and weight characteristics of the glass fiber mat arenot particularly limited, and can depend on the specific application anddesired properties of the composite board. For example, the basis weightof the glass fiber mat can be from about 50 grams per square meter toabout 150 grams per square meter. The thickness of the glass fiber matcan be, for example, from about 0.015 inch to about 0.05 inch. The basisweight and thickness characteristics can be adjusted depending upon thedesired rigidity, strength and weight of the composite board.

The thickness of the facer material may vary; for example, it may befrom about 0.01 to about 1.00 or in other embodiments from about 0.015to about 0.050 inches thick.

External Coating

In one or more embodiments, facers 14, 14′ include one or more coatinglayers (e.g., coating layers 16 and 20), and optionally coating materialdisposed within the interstices of the mat, which coating material isreferred to as penetrated coating material. As explained above, thepenetrated coating is to be distinguished from any binder used to formthe glass mat itself, such as those binders used to hold the nonwovenfibers of the glass mat together.

In one or more embodiments, external coating 16, 16′ includes an inertfiller dispersed within a binder or matrix. In one or more embodiments,the external coating includes an inorganic filler or mineral fillerdispersed throughout a binder. In one or more embodiments, the externalcoating is devoid or substantially devoid of intumescent material.

In one or more embodiments, external coating 16, 16′ may have athickness of at least 0.005 mm, in other embodiments at least 0.01 mm,in other embodiments 0.05 mm, and in other embodiments at least 0.09 mm.In these or other embodiments, coating 16, 16′ may have a thickness ofless than 1.5 mm, in other embodiments less than 1.0 mm, in otherembodiments less than 0.7 mm, in other embodiments less than 0.3 mm, andin other embodiments less than 0.1 mm.

In one or more embodiments, the concentration of filler within externalcoating 16, 16′ may be expressed as the weight of filler relative to theentire weight of the layer. In one or more embodiments, the amount offiller within the external coating 16, 16′ may be more than 0.5 wt. %,in other embodiments more than 1.0 wt. %, and in other embodiments morethan 3.0 wt. %. In these or more embodiments, the amount of fillerwithin the external coating 16, 16′ may be less than 50 wt. %, in otherembodiments less than 40 wt. %, and in other embodiments less than 30wt. %. In one or more embodiments, the amount of filler within theexternal coating 16, 16′ may be from about 0.5 to about 50 wt. %, inother embodiments from about 1.0 to about 40 wt. %, and in otherembodiments from about 3.0 to about 30 wt. %.

In one or more embodiments, the thickness of coating 16, 16′ may begreater than 0.5 mm, in other embodiments greater than 1 mm, and inother embodiments greater than 1.5 mm. In these or more embodiments, thethickness of coating 16, 16′ (as well as coating 34) may be less than 7mm, in other embodiments less than 5 mm, and in other embodiments lessthan 3 mm. In one or more embodiments, the thickness of coating 16, 16′may be from about 0.5 to about 7 mm, in other embodiments from about 1to about 5 mm, and in other embodiments from about 1.5 to about 3 mm.

In one or more embodiments, the binder may include natural or syntheticmaterials. For example, natural materials may include natural rubber,waxes and starches. Synthetic materials may include polyolefins,styrene-butadiene copolymers, polyvinyl chlorides, acrylic polymers, andmethacrylic polymers, silicones, and copolymers thereof includingfunctional copolymers thereof. For example, the binders may includestyrene-butadiene polymers bearing one or more hydrophobic moieties(e.g., fluorine-containing groups) for repelling water. Still otherexamples include, but not limited to, polyurethane coating compositions,polymeric resin coating compositions, and siloxane coating compositions,as well as polymer-modified asphalt or bitumen coating compositions.These polymers may derive from latex compositions that carry one or moreof the polymers.

In one or more embodiments, external layer 16, 16′ can include fromabout 1 wt % to about 15 wt %, or in other embodiments from about 2 toabout 10 wt %, binder based on the weight of the respective layers.

Examples of a suitable inert filler include calcium carbonate, clay,talc, mica, perlite, hollow ceramic spheres or a combination thereof. Inan exemplary embodiment, the inert filler is calcium carbonate.

In one or more embodiments, external layer 16, 16′ can include fromabout 80 wt % to about wt 98%, or in other embodiments from 85 to about95 wt % inert filler based on the weight of each respective layer.

Interfacial Layer-Intumescent Material

As suggested above, interfacial layer 20, 20′ includes intumescentmaterial dispersed within a binder. In particular embodiments, theintumescent material is expandable graphite. In one or more embodiments,interfacial layer 20, 20′, which may also be referred to as interfacialcoating 20, 20′, includes a complementary filler such as inert filler orinorganic filler. In other embodiments, interfacial layer 20, 20′ isdevoid or substantially devoid of filler other than intumescentmaterial.

In one or more embodiments, the thickness of interfacial layer 20, 20′may be greater than 1 μm, in other embodiments greater than 20 μm, andin other embodiments greater than 50 μm. In these or other embodiments,the thickness or interfacial layer 20, 20′ may be less than 5 mm, inother embodiments less than 1 mm, and in other embodiments less than 0.5mm. In one or more embodiments, the thickness of interfacial layer 20,20′ may be from about 1 μm to about 5 mm, in other embodiments fromabout 20 μm to about 1 mm, and in other embodiments from about 50 μm toabout 0.5 mm.

In one or more embodiments, the concentration of intumescent material(e.g., expandable graphite) within interfacial layer 20, 20′ may beexpressed as the weight of intumescent material relative to the entireweight of the layer. In one or more embodiments, the amount ofintumescent material within the interfacial layers may be more than 0.5wt. %, in other embodiments more than 1.0 wt. %, and in otherembodiments more than 3.0 wt. %. In these or more embodiments, theamount of intumescent material within the interfacial layers may be lessthan 50 wt. %, in other embodiments less than 40 wt. %, and in otherembodiments less than 30 wt. %. In one or more embodiments, the amountof intumescent material within the interfacial layers may be from about0.5 to about 50 wt. %, in other embodiments from about 1.0 to about 40wt. %, and in other embodiments from about 3.0 to about 30 wt. %.

In one or more embodiments, the binder may include natural or syntheticmaterials. For example, natural materials may include natural rubber,waxes and starches. Synthetic materials may include polyolefins,styrene-butadiene copolymers, polyvinyl chlorides, acrylic polymers, andmethacrylic polymers, silicones, and copolymers thereof includingfunctional copolymers thereof. For example, the binders may includestyrene-butadiene polymers bearing one or more hydrophobic moieties(e.g., fluorine-containing groups) for repelling water. Still otherexamples include, but not limited to, polyurethane coating compositions,polymeric resin coating compositions, and siloxane coating compositions,as well as polymer-modified asphalt or bitumen coating compositions.

In one or more embodiments, complementary fillers include, but are notlimited to, In one or more embodiments, the fire-resistant materials mayinclude inorganic mineral fillers such as clays, silicates, titaniumdioxide, talc (magnesium silicate), mica (mixtures of sodium andpotassium aluminum silicate), alumina trihydrate, antimony trioxide,calcium carbonate, titanium dioxide, silica, magnesium hydroxide,calcium borate ore, colemanite, and mixtures thereof.

Intumescent Materials

In one or more embodiments, intumescent materials include expandablegraphite, which may also be referred to as expandable flake graphite,intumescent flake graphite, or expandable flake, includes intercalatedgraphite in which an intercallant material is included between thegraphite layers of graphite crystal or particle. Examples ofintercallant materials include halogens, alkali metals, sulfates,nitrates, various organic acids, aluminum chlorides, ferric chlorides,other metal halides, arsenic sulfides, and thallium sulfides. In certainembodiments of the present invention, the expandable graphite includesnon-halogenated intercallant materials. In certain embodiments, theexpandable graphite includes sulfate intercallants, also referred to asgraphite bisulfate. As is known in the art, bisulfate intercalation isachieved by treating highly crystalline natural flake graphite with amixture of sulfuric acid and other oxidizing agents which act tocatalyze the sulfate intercalation.

Commercially available examples of expandable graphite include HPMSExpandable Graphite (HP Materials Solutions, Inc., Woodland Hills,Calif.) and Expandable Graphite Grades 1721 (Asbury Carbons, Asbury,N.J.). Other commercial grades contemplated as useful in the presentinvention include 1722, 3393, 3577, 3626, and 1722HT (Asbury Carbons,Asbury, N.J.).

In one or more embodiments, the expandable graphite may be characterizedas having a mean or average size in the range from about 30 μm to about1.5 mm, in other embodiments from about 50 μm to about 1.0 mm, and inother embodiments from about 180 to about 850 μm. In certainembodiments, the expandable graphite may be characterized as having amean or average size of at least 30 μm, in other embodiments at least 44μm, in other embodiments at least 180 μm, and in other embodiments atleast 300 μm. In one or more embodiments, expandable graphite may becharacterized as having a mean or average size of at most 1.5 mm, inother embodiments at most 1.0 mm, in other embodiments at most 850 μm,in other embodiments at most 600 μm, in yet other embodiments at most500 μm, and in still other embodiments at most 400 μm. Useful expandablegraphite includes Graphite Grade #1721 (Asbury Carbons), which has anominal size of greater than 300 μm.

In one or more embodiments, the expandable graphite may be characterizedas having a nominal particle size of 20×50 (US sieve). US sieve 20 hasan opening equivalent to 0.841 mm and US sieve 50 has an openingequivalent to 0.297 mm. Therefore, a nominal particle size of 20×50indicates the graphite particles are at least 0.297 mm and at most 0.841mm.

In one or more embodiments, the expandable graphite may be characterizedas having a carbon content in the range from about 75% to about 99%. Incertain embodiments, the expandable graphite may be characterized ashaving a carbon content of at least 80%, in other embodiments at least85%, in other embodiments at least 90%, in yet other embodiments atleast 95%, in other embodiments at least 98%, and in still otherembodiments at least 99% carbon.

In one or more embodiments, the expandable graphite may be characterizedas having a sulfur content in the range from about 0% to about 8%, inother embodiments from about 2.6% to about 5.0%, and in otherembodiments from about 3.0% to about 3.5%. In certain embodiments, theexpandable graphite may be characterized as having a sulfur content ofat least 0%, in other embodiments at least 2.6%, in other embodiments atleast 2.9%, in other embodiments at least 3.2%, and in other embodiments3.5%. In certain embodiments, the expandable graphite may becharacterized as having a sulfur content of at most 8%, in otherembodiments at most 5%, in other embodiments at most 3.5%.

In one or more embodiments, the expandable graphite may be characterizedas having an expansion ratio (cc/g) in the range from about 10:1 toabout 500:1, in other embodiments at least 20:1 to about 450:1, in otherembodiments at least 30:1 to about 400:1, in other embodiments fromabout 50:1 to about 350:1. In certain embodiments, the expandablegraphite may be characterized as having an expansion ratio (cc/g) of atleast 10:1, in other embodiments at least 20:1, in other embodiments atleast 30:1, in other embodiments at least 40:1, in other embodiments atleast 50:1, in other embodiments at least 60:1, in other embodiments atleast 90:1, in other embodiments at least 160:1, in other embodiments atleast 210:1, in other embodiments at least 220:1, in other embodimentsat least 230:1, in other embodiments at least 270:1, in otherembodiments at least 290:1, and in yet other embodiments at least 300:1.In certain embodiments, the expandable graphite may be characterized ashaving an expansion ratio (cc/g) of at most 350:1, and in yet otherembodiments at most 300:1.

In one or more embodiments, the expandable graphite may be characterizedas having a pH in the range from about 1 to about 12; in otherembodiments from about 1 to about 6; and in yet other embodiments fromabout 5 to about 10. In certain embodiments, the expandable graphite maybe characterized as having a pH in the range from about 4 to about 7. Inone or more embodiments, the expandable graphite may be characterized ashaving a pH of at least 1, in other embodiments at least 4, and in otherembodiments at least 5. In certain embodiments, the expandable graphitemay be characterized as having a pH of at most 10, in other embodimentsat most 7, and in other embodiments at most 6.

In one or more embodiments, the expandable graphite may be characterizedby an onset temperature ranging from about 100° C. to about 250° C.; inother embodiments from about 160° C. to about 225° C.; and in otherembodiments from about 180° C. to about 200° C. In one or moreembodiments, the expandable graphite may be characterized by an onsettemperature of at least 100° C., in other embodiments at least 130° C.,in other embodiments at least 160° C., and in other embodiments at least180° C. In one or more embodiments, the expandable graphite may becharacterized by an onset temperature of at most 250° C., in otherembodiments at most 225° C., and in other embodiments at most 200° C.Onset temperature may also be interchangeably referred to as expansiontemperature; and may also be referred to as the temperature at whichexpansion of the graphite starts.

Preparation of Construction Boards

Generally speaking, the construction boards of the present invention canbe prepared by using known techniques that are adapted in view of theteachings of this invention. In general, processes for the manufactureof polyurethane or polyisocyanurate insulation boards are known in theart as described in U.S. Pat. Nos. 6,117,375, 6,044,604, 5,891,563,5,573,092, U.S. Publication Nos. 2004/0109983, 2003/0082365,2003/0153656, 2003/0032351, and 2002/0013379, as well as U.S. Ser. Nos.10/640,895, 10/925,654, and 10/632,343, which are incorporated herein byreference.

As the skilled person appreciates, foam may be produced by developing orforming polyurethane and/or polyisocyanurate foam in the presence of ablowing agent. The foam may be prepared by contacting an A-side streamof reagents with a B-side stream of reagents and depositing the mixtureor developing foam onto a laminator carrying a facer, which may includeone or more of the coating and/or fire-resistant layers describedherein. The A-side stream may include an isocyanate compound and theB-side may include an isocyanate-reactive compound.

A-Side Stream

As suggested above, the A-side stream includes an isocyanate. Suitableisocyanate-containing compounds useful for the manufacture ofpolyisocyanurate construction board are generally known in the art andembodiments of this invention are not limited by the selection of anyparticular isocyanate-containing compound. Useful isocyanate-containingcompounds include polyisocyanates. Useful polyisocyanates includearomatic polyisocyanates such as diphenyl methane diisocyanate in theform of its 2,4′-, 2,2′-, and 4,4′-isomers and mixtures thereof. Themixtures of diphenyl methane diisocyanates (MDI) and oligomers thereofmay be referred to as “crude” or polymeric MDI, and thesepolyisocyanates may have an isocyanate functionality of greater than 2.Other examples include toluene diisocyanate in the form of its 2,4′ and2,6′-isomers and mixtures thereof, 1,5-naphthalene diisocyanate, and1,4′ diisocyanatobenzene. Exemplary polyisocyanate compounds includepolymeric Rubinate 1850 (Huntsmen Polyurethanes), polymeric LupranateM70R (BASF), and polymeric Mondur 489N (Bayer).

B-Side Stream

As suggested above, the B-side stream includes an isocyanate-reactivecompound, and may also include flame retardants, catalysts,emulsifiers/solubilizers, surfactants, blowing agents, fillers,fungicides, anti-static substances, water and other ingredients that areconventional in the art.

An exemplary isocyanate-reactive component is a polyol. The term polyol,or polyol compound, includes diols, polyols, and glycols, which maycontain water as generally known in the art. Primary and secondaryamines are suitable, as are polyether polyols and polyester polyols.Useful polyester polyols include phthalic anhydride based PS-2352(Stepen), phthalic anhydride based polyol PS-2412 (Stepen), teraphthalicbased polyol 3522 (Invista), and a blended polyol TR 564 (Huntsman).Useful polyether polyols include those based on sucrose, glycerin, andtoluene diamine. Examples of glycols include diethylene glycol,dipropylene glycol, and ethylene glycol. Suitable primary and secondaryamines include, without limitation, ethylene diamine, anddiethanolamine. In one or more embodiments, a polyester polyol isemployed. In one or more embodiments, the present invention may bepracticed in the appreciable absence of any polyether polyol. In certainembodiments, the ingredients are devoid of polyether polyols.

Catalysts are believed to initiate the polymerization reaction betweenthe isocyanate and the polyol, as well as a trimerization reactionbetween free isocyanate groups when polyisocyanurate foam is desired.While some catalysts expedite both reactions, two or more catalysts maybe employed to achieve both reactions. Useful catalysts include salts ofalkali metals and carboxylic acids or phenols, such as, for examplepotassium octoate; mononuclear or polynuclear Mannich bases ofcondensable phenols, oxo-compounds, and secondary amines, which areoptionally substituted with alkyl groups, aryl groups, or aralkylgroups; tertiary amines, such as pentamethyldiethylene triamine(PMDETA), 2,4,6-tris [(dimethylamino)methyl]phenol, triethyl amine,tributyl amine, N-methyl morpholine, and N-ethyl morpholine; basicnitrogen compounds, such as tetra alkyl ammonium hydroxides, alkalimetal hydroxides, alkali metal phenolates, and alkali metal acholates;and organic metal compounds, such as tin(II)-salts of carboxylic acids,tin(IV)-compounds, and organo lead compounds, such as lead naphthenateand lead octoate.

Surfactants, emulsifiers, and/or solubilizers may also be employed inthe production of polyurethane and polyisocyanurate foams in order toincrease the compatibility of the blowing agents with the isocyanate andpolyol components.

Surfactants may serve two purposes. First, they may help toemulsify/solubilize all the components so that they react completely.Second, they may promote cell nucleation and cell stabilization.Exemplary surfactants include silicone co-polymers or organic polymersbonded to a silicone polymer. Although surfactants can serve bothfunctions, a more cost effective method to ensureemulsification/solubilization may be to use enoughemulsifiers/solubilizers to maintain emulsification/solubilization and aminimal amount of the surfactant to obtain good cell nucleation and cellstabilization. Examples of surfactants include Pelron surfactant 9920,Goldschmidt surfactant B8522, and GE 6912. U.S. Pat. Nos. 5,686,499 and5,837,742 are incorporated herein by reference to show various usefulsurfactants.

Suitable emulsifiers/solubilizers include DABCO Ketene 20AS (AirProducts), and Tergitol NP-9 (nonylphenol+9 moles ethylene oxide).

Useful blowing agents include isopentane, n-pentane, cyclopentane,alkanes, (cyclo) alkanes, hydrofluorocarbons, hydrochlorofluorocarbons,fluorocarbons, fluorinated ethers, alkenes, alkynes, carbon dioxide,hydrofluoroolefins (HFOs) and noble gases.

Flame Retardants may be used in the production of polyurethane andpolyisocyanurate foams, especially when the foams contain flammableblowing agents such as pentane isomers. Useful flame retardants includetri(monochloropropyl) phosphate (a.k.a. tris (cloro-propyl) phosphate),tri-2-chloroethyl phosphate (a.k.a tris(chloro-ethyl) phosphate),phosphonic acid, methyl ester, dimethyl ester, and diethyl ester. U.S.Pat. No. 5,182,309 is incorporated herein by reference to show usefulblowing agents.

Exemplary non-halogenated solid flame retardants include magnesiumhydroxide, aluminum trihydrate, zinc borate, ammonium polyphosphate,melamine polyphosphate, and antimony oxide (Sb₂O₃). Magnesium hydroxide(Mg(OH)₂) is commercially available under the tradename Vertex™ 60,ammonium polyphosphate is commercially available under the tradenameExolite™ AP 760 (Clarian), melamine polyphosphate is available under thetradename Budit™ 3141 (Budenheim), and antimony oxide (Sb₂O₃) iscommercially available under the tradename Fireshield™. Exemplarynon-halogenated liquid flame retardants include triethylphosphate, suchas that available under the tradename TEP (Lanxess). Exemplary reactiveflame retardants include liquid reactive phosphates such as thoseavailable under the tradenames E06-16 (ICL) FYROL (ICL).

The respective streams can be mixed within, for example, a mixhead toproduce a reaction mixture. The mixture can then be deposited onto afacer that is positioned within and carried by a laminator. Inaccordance with the present invention, the mixture can be deposited ontoa facer having opposed coating layers as described above (e.g., theexternal coating layer and the interfacial coating layer). Specifically,the foam mixture is deposited directly onto the planar surface of thefacer carrying the interfacial coating layer.

While in the laminator, the reaction mixture rises and can be married toa second facer to form a composite, which may also be referred to as alaminate, wherein the foam is sandwiched between upper and lower facers.Likewise, in accordance with this invention, the second facer may carrya pair of opposed coating layers. In one or more embodiments, the faceris mated with the rising foam so that the interfacial coating layer ofthe second facer contacts the rising foam.

In one or more embodiments, the coating layers carried by the facer areapplied to a glass mat substrate by applying a liquid coatingcomposition by employing conventional coating techniques. For example,one or both coatings may be applied by gravure coating, reverse rollcoating, slot die coating, immersion (dip) coating, knife coating,electrohydrodynamic spraying, and the like. In one or more embodiments,these liquid coating compositions (i.e., those forming 20, 20′) mayinclude at least 0.5 wt. %, in other embodiments at least 1.0 wt. %, inother embodiments at least 3 wt. %, in other embodiments at least 5 wt.%, and in other embodiments at least 7 wt. % filler, based on the entireweight of the liquid composition. In these or other embodiments, theseliquid coating compositions include at most 40 wt. %, in otherembodiments at most 30 wt. %, in other embodiments at most 25 wt. %, inother embodiments at most 20 wt. %, and in other embodiments at most 15wt. % filler, based on the entire weight of the liquid composition. Inone or more embodiments, these liquid coating compositions include fromabout 0.5 to about 40, in other embodiments from about 1 to about 25,and in other embodiments from about 2 to about 20 wt. % filler, basedupon the entire weight of the liquid composition.

Similarly, the interfacial coating, which forms the interfacial layers,is applied to respective substrates in the form of a liquid coatingcomposition that includes expandable graphite. As the skilled personwill appreciate, this coating, including the expandable graphite, isapplied to a planar surface of the substrate that is opposite the planarsurface where the external coating may be applied. The coatingcomposition forming interfacial layers may be applied by gravurecoating, reverse roll coating, slot die coating, immersion (dip)coating, knife coating, electrohydrodynamic spraying, and the like. Inone or more embodiments, these liquid coating compositions may includeat least 0.5 wt. %, in other embodiments at least 1.0 wt. %, in otherembodiments at least 3 wt. %, in other embodiments at least 5 wt. %, andin other embodiments at least 7 wt. % expandable graphite, based on theentire weight of the liquid composition. In these or other embodiments,these coating compositions include at most 40 wt. %, in otherembodiments at most 30 wt. %, in other embodiments at most 25 wt. %, inother embodiments at most 20 wt. %, and in other embodiments at most 15wt. % fire-resistant material (e.g., expandable graphite), based on theentire weight of the liquid composition. In one or more embodiments,these compositions include from about 0.5 to about 40, in otherembodiments from about 1 to about 25, and in other embodiments fromabout 2 to about 20 wt. % expandable graphite, based upon the entireweight of the liquid composition.

In one or more embodiments, the coating layers, as well as thepenetrated coating material, allow for a relatively high degree of airpermeability of the facer. In one or more embodiments, the coatinglayers are discontinuous or irregular (e.g., have an irregularthickness), and the penetrated coating may not fill all of theinterstices of the mat, either of which may contribute to the relativelyhigh degree of air permeability of the facer.

In one or more embodiments, where the facer includes external andinternal coating layers (e.g., layers 16 and 30), as well as interfacialcoating layer (e.g., 20), derives from employing a double-coated glassmat, which is a glass mat that includes a coating material, includinginert filler, applied to both planar surfaces of the glass mat. Anymethod suitable for applying a binding composition or coating to a glassfiber mat or impregnating a glass fiber mat with a binding compositionor coating may be used to apply the first binding composition to theupper surface of the at least one glass fiber mat and the second bindingcomposition to the lower surface of the at least one glass fiber mat.For example, the first and second binding composition can be applied byair spraying, dip coating, knife coating, roll coating, or filmapplication such as lamination/heat pressing. The ability to producecoated facers is known as described in U.S. Pat. Nos. 5,102,728,5,112,678, and 7,138,346, which are incorporated herein by reference.

In one or more embodiments, the double-coated facer is characterized byan air permeability, which may also be referred to as porosity, asdetermined by ARC-WT-006 (which correlates to TAPPI T460om-96), of lessthan 300, in other embodiments less than 250, in other embodiments lessthan 200, in other embodiments less than 150, in other embodiments lessthan 100, in other embodiments less than 70, in other embodiments lessthan 50, in other embodiments less than 40, and in other embodimentsless than 30 Gurley seconds/300 cubic centimeters.

In one or more embodiments, the double-coated facer is characterized bya coating weight of greater than 500, in other embodiments greater than600, in other embodiments greater than 700, in other embodiments greaterthan 800, in other embodiments greater than 810, in other embodimentsgreater than 820, in other embodiments greater than 830, in otherembodiments greater than 840, in other embodiments greater then 850, inother embodiments greater then 860, in other embodiments greater 870, inother embodiments greater 880, in other embodiments greater than 890,and in other embodiments greater than 900 grams per square meter. In oneor more embodiments, the coating weight is less than 1000, in otherembodiments less than 950, and in other embodiments less than 920 gramsper square meter. As used herein, the term “coating weight” means theweight of the coating per area of the at least one glass fiber mat,which includes both coating layers as well as the penetrated coatingmaterial.

The composite, while in laminator, or after removal from laminator, isexposed to heat that may be supplied by, for example, oven. For example,laminator may include an oven or hot air source that heats the slats andside plates of the laminator and there through transfers heat to thelaminate (i.e., to the reaction mixture). Once subjected to this heat,the foam composite can undergo conventional finishing within a finishingstation, which may include, but is not limited to, trimming and cutting.

INDUSTRIAL APPLICABILITY

In one or more embodiments, the construction boards of this inventionmay be employed in roofing or wall applications. In particularembodiments, the construction boards are used in flat or low-sloperoofing system.

As shown in FIG. 3, roofing system 30 includes a roof deck 32 havinginsulation board 34, which may be fabricated according to practice ofthis invention, disposed thereon. An optional high density board 36,which may also be fabricated according to practice of this invention,positioned above, relative to the roof deck, insulation board 34. Awater-protective layer or membrane 38 is disposed on top or above highdensity board 36. In alternate embodiments, not shown, optional highdensity board 36 may be below insulation board 34 relative to the roofdeck.

Practice of this invention is not limited by the selection of anyparticular roof deck. Accordingly, the roofing systems of this inventioncan include a variety of roof decks. Exemplary roof decks includeconcrete pads, steel decks, wood beams, and foamed concrete decks.

Practice of this invention is likewise not limited by the selection ofany water-protective layer or membrane. As is known in the art, severalmembranes can be employed to protect the roofing system fromenvironmental exposure, particularly environmental moisture in the formof rain or snow. Useful protective membranes include polymericmembranes. Useful polymeric membranes include both thermoplastic andthermoset materials. For example, and as is known in the art, membraneprepared from poly(ethylene-co-propylene-co-diene) terpolymer rubber orpoly(ethylene-co-propylene) copolymer rubber can be used. Roofingmembranes made from these materials are well known in the art asdescribed in U.S. Pat. Nos. 6,632,509, 6,615,892, 5,700,538, 5703,154,5,804,661, 5,854,327, 5,093,206, and 5,468,550, which are incorporatedherein by reference. Other useful polymeric membranes include those madefrom various thermoplastic polymers or polymer composites. For example,thermoplastic olefin (i.e., TPO), thermoplastic vulcanizate (i.e., TPV),or polyvinylchloride (PVC) materials can be used. The use of thesematerials for roofing membranes is known in the art as described in U.S.Pat. Nos. 6,502,360, 6,743,864, 6,543,199, 5,725,711, 5,516,829,5,512,118, and 5,486,249, which are incorporated herein by reference. Inone or more embodiments, the membranes include those defined by ASTMD4637-03 and/or ASTM D6878-03.

Still in other embodiments, the protective membrane can includebituminous or asphalt membranes. In one embodiment, these asphaltmembranes derive from asphalt sheeting that is applied to the roof.These asphalt roofing membranes are known in the art as described inU.S. Pat. Nos. 6,579,921, 6,110,846, and 6,764,733, which areincorporated herein by reference. In other embodiments, the protectivemembrane can derive from the application of hot asphalt to the roof.

Other layers or elements of the roofing systems are not excluded by thepractice of this invention. For example, and as is known in the art,another layer of material can be applied on top of the protectivemembrane. Often these materials are applied to protect the protectivemembranes from exposure to electromagnetic radiation, particularly thatradiation in the form of UV light. In certain instances, ballastmaterial is applied over the protective membrane. In many instances,this ballast material simply includes aggregate in the form of rock,stone, or gravel; U.S. Pat. No. 6,487,830, is incorporated herein inthis regard.

The construction boards of this invention can be secured to a buildingstructure by using various known techniques. For example, in one or moreembodiments, the construction boards can be mechanically fastened to thebuilding structure (e.g., the roof deck). In other embodiments, theconstruction boards can be adhesively secured to the building structure.

Various modifications and alterations that do not depart from the scopeand spirit of this invention will become apparent to those skilled inthe art. This invention is not to be duly limited to the illustrativeembodiments set forth herein.

What is claimed is:
 1. A construction board comprising: a foam bodyhaving first and second planar surfaces, said foam body including apolyisocyanurate foam matrix defining a plurality of closed cells, saidclosed cells being at least substantially devoid of hydrocarbon blowingagents, and said foam body being characterized by a density, pursuant toASTM C303, of at least 2.5 lbs/ft³; and a facer disposed on a planarsurface of said foam body, said facer including a glass substrate havingan internal planar surface proximate to said foam body and an externalplanar surface opposite said foam body, a first coating disposed on saidexternal surface, and a second coating disposed on or proximate to saidinternal surface, where said first coating disposed on said externalsurface includes an inert filler, and where said second coating disposedon or proximate to said internal surface includes intumescent material.2. The construction board of claim 1, where said inert filler includescalcium carbonate.
 3. The construction board of claim 1, where saidintumescent material includes expandable graphite.
 4. The constructionboard of claim 1, where said first coating includes a polymeric binderin which said inert filler is dispersed.
 5. The construction board ofclaim 1, where said second coating includes a polymeric binder in whichsaid intumescent material is dispersed.
 6. The construction board ofclaim 1, where said closed cells include carbon dioxide, air, or apartial vacuum.
 7. The construction board of claim 1, where said closedcells include less than 2 percent by volume hydrocarbon blowing agent.8. The construction board of claim 1, where said facer is a first facer,and where said construction board includes a second facer disposed on aplanar surface of said foam body opposite said first facer, said secondfacer including a glass substrate having an internal planar surfaceproximate to said foam body and an external planar surface opposite saidfoam body, a first coating disposed on said external surface, and asecond coating disposed on or proximate to said internal surface, wheresaid first coating disposed on said external surface includes an inertfiller, and where said second coating disposed on or proximate to saidinternal surface includes intumescent material.